Peterborough City Council – Demolition of the Corn Exchange, Peterborough

Connell Brothers were appointed as demolition contractors for the demolition of The Corn Exchange building in the centre of Peterborough.

The city was undergoing a substantial facelift and in addition to the demolition of the Corn Exchange the surrounding area was being made into a predominantly pedestrian zone by other contractors. The Corn Exchange was in very close proximity to a 12th Century Church as well as a number of listed buildings. Within the Corn Exchange was an EDF electrical sub-station proving power to surrounding premises and the shopping centre adjacent to the site.

The building had been used as an office with a Post Office located on the ground floor together with other retail outlets. The 6 storey structure consisted of a reinforced concrete frame with concrete and pot flooring and precast concrete cladding to the external walls.

Due the very congested nature of the site various items required relocating in order to erect the perimeter hoarding and gain safe access and egress to the works by creating a one way traffic system and to provide protection to the adjacent church. These items included street lights, road signs and CCTV cameras. Various premises surrounding the site were identified as a potential risk from falling roof tiles and protection measures were fitted at gutter level as a precaution. These works were undertaken out of hours to minimise disruption to retailers.

A large number of items had been identified for re-use by the client. These were carefully removed and taken to an off site storage area where various parties could claim them. Following the removal of the salvageable items the building was soft stripped and the asbestos was removed by Connell Brothers in house operatives.

The building was separated by hand from the EDF sub-station to prevent any accidental damage. An excavator was brought to site and the two storey podium demolished by pulverising it in situ. Scaffold was erected to all four sides of the building to provide a screen to prevent any dust from the works escaping the site. During this time it was decided to demolish the EDF substation as a new substation was required as part of the final works. The site welfare facilities were relocated to the area formally occupied by the podium, freeing up the space in front of the substation and along the inside of the hoarding to enable EDF to carry out their works.

Connell Brothers then provided a secure access and works area and vacated the site for 5 weeks to allow EDF to excavate and lay new cables and to isolate the substation.

Upon our return the main demolition commenced. Props were brought to the site and installed on four floors to distribute the weight of the demolition plant safely. Once installed a mobile crane was used to lift two 3 ½ T excavators and a skid steer loader onto the roof. An area of the roof was barriered off as a “no go “ zone due to an internal staircase below where no propping could be installed. The excavators then pr5oceeded to demolish the roof of the building and the skid steer loader deposited the debris down the pre-prepared lift shaft to ground floor level where they were removed by an excavator and taken off site for recycling.

Demolition of the main building continued using the floor by floor method until the entire structure was brought down to a level where ground based excavators could take over. The building was then demolished down to the ground floor slab and the site cleared.

In order to avoid disrupting the public part of the works adjacent to the hoarding was carried out at night and pedestrian diversions placed outside the site as an additional safety measure.

Once the site was cleared the removal of the ground floor slab could be carried out. As part of these works the foundation pads beneath each column base were recorded and if they protruded above the level required for the landscaping works they were removed. Those left in place were recorded on a drawing for others.

During the excavation works the Client appointed an archaeologist to oversee the works. Various items were recovered from the site including the remnants of leather shoes, various bones and shards of clay pots. It was also evident that the original ground had been at a much lower level, approximately the same level as the adjacent church yard, as there were distinct levels present in the excavations.

The site was left covered in crushed aggregate at the required level to enable the streetworks contractor to carry out his works.

Throughout the works Connell brothers enjoyed a close working relationship with both the client and the CDM Co-Ordinator. Due to the close proximity of the adjacent shops and the Church continual liaison was required in order to execute the works with the minimum disruption to everyday life within the town centre.

At various times the church requested works be suspended for funeral services with which Connell Brothers were happy to comply. The church was also subject to extensive lilt monitoring by the client to determine if the demolition works had any effect on the existing structure, the results of this monitoring show that the methods utilised for the demolition works had no effect on the structure of the church. Monitoring was also carried out to adjacent building with the same results. Connell brothers also carried out vibration and noise monitoring throughout the works to ensure all activities fell within the specified parameters.

The careful selection of demolition plant and the method of carrying out the demolition works resulted in the project being carried out on time with no damage to adjacent property and very minimal disruption to Peterboroughs residents.

CLIENT:Peterborough City Council
Manor Drive House
Manor Drive
Paston
Peterborough